As known in the art, fan-out wafer-level packaging (FOWLP) is a packaging process in which contacts of a semiconductor die are redistributed over a larger area through a redistribution layer (RDL) that is typically formed on a substrate such as a TSV interposer.
The RDL is typically defined by the addition of metal and dielectric layers onto the surface of the wafer to re-route an Input/Output (I/O) layout into a looser pitch footprint. Such redistribution requires thin film polymers such as benzocyclobutene (BCB), polyimide (PI), or other organic polymers and metallization such as Al or Cu to reroute the peripheral pads to an area array configuration.
The TSV interposer is costly because fabricating the interposer substrate with TSVs is a complex process. Thus, forming FOWLP products that include an interposer having a TSV interposer may be undesirable for certain applications.
In wafer-level packaging, the wafer and dies mounted on the wafer are typically covered with a relatively thick layer of molding compound. The thick layer of the molding compound results in increased warping of the packaging due to coefficient of thermal expansion (CTE) mismatch, and the thickness of the packaging. It is known that wafer warpage continues to be a concern.
Warpage can prevent successful assembly of a die-to-wafer stack because of the inability to maintain the coupling of the die and wafer. Warpage issue is serious, especially in a large-sized wafer, and has raised an obstacle to a wafer-level semiconductor packaging process that requires a fine-pitch RDL process. Therefore, there remains a need in the art for an improved method of manufacturing wafer-level packages.